Methods of forming composite materials

ABSTRACT

A method of forming a substantially air-impermeable composite material includes introducing a sheet-form film and a loop material into a nip formed between a first roll and a second roll, introducing molten resin into the nip between the film and the loop material, and allowing the molten resin to cool so that the film becomes attached to the loop material by the cooled resin.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/324,545, filed on Apr. 15, 2010, which is incorporated by referenceherein.

TECHNICAL FIELD

This invention relates to methods of forming composite materials.

BACKGROUND

Multi-layered composite materials are used for various different typesof applications. In certain cases, such composite materials areconstructed in a way to make the composite materials substantiallyliquid-impermeable and/or air-impermeable. Liquid-impermeable and/orair-impermeable composite materials can be used in products in which itis useful to prevent liquid and/or air from escaping from the productduring use.

SUMMARY

In one aspect of the invention, a method of forming a composite materialincludes introducing a sheet-form film and a hook-engageable materialinto a nip formed between a first roll and a second roll, introducingmolten resin into the nip between the film and the hook-engageablematerial, and allowing the molten resin to cool so that the film becomesattached to the hook-engageable material by the cooled resin. Each ofthe film, the hook-engageable material, and the molten resin includes atleast about 85 percent by weight of a first polymer.

In another aspect of the invention, a method of forming a compositematerial includes introducing a sheet-form film and a hook-engageablematerial into a nip formed between a first roll and a second roll,introducing molten resin into the nip between the film and thehook-engageable material, and allowing the molten resin to cool so thatthe film becomes attached to the hook-engageable material by the cooledresin. Each of the film, the hook-engageable material, and the moltenresin includes at least about 90 percent by weight of a first polymer,the composite material is substantially air-impermeable, and fibersextending from a surface of the hook-engageable material are capable ofengaging hooks of hook fasteners after the film is attached to thehook-engageable material by the cooled resin.

Embodiments can include one or more of the following features.

In some embodiments, the composite material is substantiallyair-impermeable.

In certain embodiments, the composite material has an air-permeabilityof 0 cm³/s/cm2.

In some embodiments, fibers extending from a surface of thehook-engageable material are capable of engaging hooks of hook fastenersafter the film is attached to the hook-engageable material by the cooledresin.

In certain embodiments, the first polymer is polypropylene.

In some embodiments, the film and the hook-engageable material consistessentially of polypropylene.

In certain embodiments, the molten resin is at least about 90 percent byweight polypropylene.

In some embodiments, the molten resin further includes polyethylene.

In certain embodiments, the hook-engageable material includes a 17 gramsper square meter spunbond polypropylene substrate through which aplurality of loop shaped staple fibers extend.

In some embodiments, the hook-engageable material includes a 30 gramsper square meter SMS polypropylene substrate through which a pluralityof loop shaped staple fibers extend.

In certain embodiments, the molten resin introduced into the nip has athickness of about one mil, the film has a thickness of about threemils, and the hook-engageable material has a weight of about 1.3 toabout 2.0 osy.

In some embodiments, the hook-engageable material has a basis weight ofabout 1.3 to about 1.6 osy.

In certain embodiments, the molten resin is at a temperature of at leastabout 500 degrees Fahrenheit (e.g., about 550 degrees Fahrenheit toabout 600 degrees Fahrenheit, about 580 degrees Fahrenheit) whenintroduced into the nip.

In some embodiments, the film is a cast film.

In certain embodiments, the molten resin is introduced into the nip in amanner such that the molten resin contacts the film and thehook-engageable material at substantially the same time.

In some embodiments, the molten resin is introduced into the nip byapplying the molten resin to the hook-engageable material and rotatingthe first and second rolls to carry the film, the hook-engageablematerial, and the molten resin into the nip.

In certain embodiments, the molten resin is introduced into the nip byapplying the molten resin to the film and rotating the first and secondrolls to carry the film, the hook-engageable material, and the moltenresin into the nip.

In some embodiments, at least one of the first and second rolls ischilled to facilitate cooling of the molten resin.

In certain embodiments, both of the first and second rolls are chilled.

In some embodiments, the method further includes embossing the compositematerial.

In certain embodiments, embossing the composite material includespassing the composite material between an embossing roll and a backingroll. The embossing roll has a plurality of raised features thatcompress the composite material between the embossing roll and thebacking roll.

In some embodiments, the embossing roll is a heated roll.

Embodiments can include one or more of the following advantages.

In certain embodiments, the composite materials formed using the variousmethods described herein are formed substantially entirely of a singletype of polymer (e.g., polypropylene). Each component or layer of thecomposite material can, for example, include at least about 85 percentby weight (e.g., at least about 90 percent by weight, at least about 95percent by weight) of the single type of polymer. Such compositematerials can, for example, be easily recycled. In addition, suchcomposite materials can provide improved weldability. For example,because the various components of the composite material are formed ofsubstantially entirely the same type of material, it is relatively easyto thermally bond those components together.

In some embodiments, the composite materials formed using the variousmethods described herein are air-impermeable. As a result, the compositematerials can be used to form inflatable bladders (e.g., inflatablebladders used in medical products, such as inflatable compressiondevices). The composite materials can alternatively or additionally besubstantially liquid-impermeable, which allows the composite materialsto be used as liquid barriers. Such liquid barriers can beadvantageously used in products, such as medical cold wraps, where it isdesirable to prevent a freezable cooling solution or water from meltingand leaking out of the product.

In certain embodiments, the composite materials formed using the variousmethods described herein include a hook-engageable surface. In suchembodiments, the composite materials can be used to form products thatbenefit from being releasably fastened. Examples of such productsinclude medical wraps and compression devices.

In some embodiments, the composite material is embossed before beingformed into or incorporated into a product. It has been found that theembossed regions of the composite material facilitate folding or bendingof the composite material. When inflatable products, such as medicalcompression devices, are formed using the embossed composite material,the noise associated with inflating the product can be reduced as aresult of the embossed composite material. For example, crinkling noisesoften associated with the inflation of relatively thin materials can bereduced due to the facilitated folding or bending of the compositematerial along the embossed regions. This can be particularlyadvantageous for blood pressure cuffs used with blood pressuremonitoring devices that detect audible signals while inflating anddeflating the cuff.

Certain methods described herein can be used to rapidly and efficientlyproduce composite materials that are formed substantially entirely of asingle type of polymer (e.g., polypropylene), that are substantiallyair-impermeable and/or liquid impermeable, and that include ahook-engageable surface. It has been discovered, for example, thatsufficient amounts of molten resin polymer can be applied between apolymeric film and polymeric loop material to achieve a substantiallyair-impermeable and/or liquid-impermeable composite material withoutdestroying the functionality of the loops of the loop material, evenwhen the molten resin and the loop material are formed substantiallyentirely of the same type of polymeric material (e.g., even when atleast about 85 percent by weight of the molten resin and at least about85 percent by weight of the loop material is the same type of polymericmaterial, such as polypropylene) and thus have similar meltingtemperatures.

Other aspects, features, and advantages will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic of a lamination system during use to form asubstantially air-impermeable composite material.

FIG. 2 is an enlarged view of region 2 in FIG. 1, showing loops, whichare capable of engaging hooks of hook fastener products, extending froma loop material layer of the composite material.

FIG. 3 is an enlarged view of region 3 in FIG. 1, showing the multiplebonded layers of the composite material.

FIGS. 4 and 5 are front and side views, respectively, of a bloodpressure cuff manufactured in part from substantially air-impermeablecomposite material formed using the method schematically illustrated inFIG. 1.

FIG. 6 illustrates the blood pressure cuff of FIGS. 4 and 5 during use.

FIG. 7 illustrates a method of manufacturing multiple blood pressurecuffs of the type shown in FIGS. 4-6 by folding a single sheet of thecomposite material of FIG. 1 and then welding overlapping regions of thefolded sheet together.

FIG. 8 illustrates an alternative method of manufacturing multiple bloodpressure cuffs of the type shown in FIGS. 4-6 by welding two sheets ofthe composite material of FIG. 1 together.

FIG. 9 is a front view of a sequential compression device manufacturedin part from substantially air-impermeable composite material formedusing the method schematically illustrated in FIG. 1.

FIG. 10 illustrates the sequential compression device of FIG. 9configured for use.

FIG. 11 is a perspective view of a urinary drain bag.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates a lamination system 100 during use. Asshown in FIG. 1, system 100 includes a pressure roll 102 and two backingrolls 104 and 106. Rolls 102 and 104 are positioned adjacent one anotherand form a nip 108 between their peripheral surfaces. Pressure roll 102and backing roll 104 are connected to motors that are configured torotate rolls 102 and 104 in opposite directions during use, as indicatedby arrows 110 and 112. When operated in this manner, pressure roll 102and backing roll 104 can cooperate to draw material (e.g., film, loopmaterial, and/or resin) through nip 108 while applying pressure to thematerial passing through nip 108.

Backing roll 106 is positioned adjacent pressure roll 102 on theopposite side of pressure roll 102 from backing roll 104. Backing roll106 is equipped with bearings such that backing roll 106 can rotate inresponse to the rotation of pressure roll 102. Backing roll 106 servesas a support for pressure roll 102 to help prevent pressure roll 102from bowing outward as a result of increased pressure within nip 108. Asa result, backing roll 106 helps to ensure that a desired uniformpressure is maintained in nip 108 during use.

Pressure roll 102 is a steel roll coated with polytetrafluoroethylene(PTFE). Typically, pressure roll 102 has a diameter of about 18 inchesto about 24 inches. Backing rolls 104 and 106 are formed of steel andare uncoated. Each of rolls 102, 104, and 106 is capable of beingchilled. For example, these rolls can included cooling passages throughwhich a cooling liquid, such as water, can travel during use. Thecooling liquid can be forced through the passages continuously duringuse to maintain the rolls at a reduced temperature.

A slot die extruder 114 is positioned above nip 108. Extruder 114includes a die 115 through which molten resin is extruded during use.Extruder 114 is adjustable both vertically and horizontally such thatextruder die 115 can be positioned at multiple different locationsrelative to nip 108.

Two rotatable shafts 116 and 118 are positioned above rolls 102 and 104.Rotatable shafts 116 and 118 are connected to motors that can driveshafts 116 and 118 at multiple different rotational speeds. As shown inFIG. 1, shaft 116 is configured such that a film roll 128 can be loadedthereon, and shaft 118 is configured such that a loop material roll 130can be loaded thereon. As described below, during use, film 122 fromfilm roll 128 and loop material 124 from loop material roll 130 can beintroduced into nip 108 by rotating shafts 116 and 118, causing therolls 128, 130 to unwind.

System 100 also includes another rotatable shaft referred to as a winder120. Winder 120, like shafts 116 and 118, is connected to a motor thatcan drive winder 120 at multiple different rotational speeds. Asdescribed below, a substantially air-impermeable composite material 121exiting nip 108 can be wound onto winder 120 for storage, shipment, orfurther processing by rotating winder 120. The rotational speeds ofrolls 102, 104, 106, shafts 116, 118, and winder 120 can be controlledso that a desired tension is applied to the composite material exitingnip 108 and being wound onto winder 120.

Still referring to FIG. 1, an exemplary method of manufacturingsubstantially air-impermeable composite material 121 will now bedescribed. During the manufacturing process, sheet-form film 122, loopmaterial 124, and molten resin 126 are delivered to nip 108. Film 122and loop material 124 are delivered to nip 108 from rolls 128 and 130 byrotating shafts 116 and 118 on which those rolls are mounted, and moltenresin 126 is extruded into nip 108 from extruder 114. In the exemplarymethod, film 122, loop material 124, and molten resin 126 are formedsubstantially entirely of the same type of material. In particular, eachof those components is formed substantially entirely of polypropylene.As discussed below, one or more of these components may include apolymer or polymers different from polypropylene, but the vast majority(e.g., at least about 85 percent by weight) of the materials used toform these components is polypropylene.

The melting temperatures of the materials from which film 122, loopmaterial 124, and molten resin 126 are formed typically differ from oneanother by no more than about 25 degrees Fahrenheit (e.g., no more thanabout 20 degrees Fahrenheit, no more than about 15 degrees Fahrenheit,no more than about 10 degrees Fahrenheit). As discussed above, film 122,loop material 124, and molten resin 126 each include a substantialamount of polypropylene. Thus, substantial portions of the material fromwhich these components are formed will have similar (e.g., substantiallythe same) melting temperatures. As a result of the similar meltingtemperatures of these materials, it can be quite complicated to bondmolten resin 126 to loop material 124 without melting the loops of loopmaterial 124. However, as discussed below, it has been found that thiscan be accomplished by using manufacturing process parameters andmaterials described herein.

Film 122 is a sheet-form polypropylene cast film having a thickness ofabout one mil to about five mils (e.g., about three mils). The use offilm 122 in combination with molten resin 126 helps to ensure thatcomposite material 121 is substantially air-impermeable.

Referring briefly to FIG. 2, which is an enlarged view of region 2 inFIG. 1, loop material 124 includes a spunbond polypropylene substrate125 having polypropylene staple fibers 127 and 129 needled therethroughto form loops 131 that extend from one side of substrate 125. Substrate125 has a basis weight of about 17 grams per square meter. Staple fibers127 and 129 are provided on substrate 125 in a 4:1 ratio. Staple fibers127 are available from Asota Mills, under product number L10D. Staplefibers 129 are available from Asota Mills, under product number CL10.Loop material 124 has an overall basis weight of about 1.3 ounces persquare yard (osy) to about 1.6 osy (e.g., about 1.47 osy).

In order to form loop material 124, staple fibers 127 and 129 areprovided on the surface of substrate 125 to form a staple fiber layer.The combination of substrate 125 and staple fibers 127 and 129 are thenfed through a needling machine that includes forked needles positionedabove the staple fibers 127, 129. As substrate 125 and staple fibers127, 129 pass under the needles, the needles are driven through thestaple fiber layer and substrate 125. Due to the construction of theneedles, as the needles are driven downward through substrate 125, theycarry some of staple fibers 127, 129 through substrate 125 to form loops131. As the needles are then retracted out of substrate 125, the loopedstaple fibers 131 remain extending from the under side of substrate 125opposite the staple fiber layer. Exemplary methods of forming loopmaterials similar to loop material 124 are described in greater detailin US 2004/0157036 and US 2009/0203280, which are incorporated byreference herein.

Referring again to FIG. 1, molten resin 126 is a blend of polypropyleneand a small amount of polyethylene. The blend typically includes atleast about 85 percent by weight (e.g., at least about 90 percent byweight, at least about 95 percent by weight) polypropylene and at mostabout 15 percent by weight (e.g., at most about 10 percent by weight, atmost about 5 percent by weight) polyethylene. The small amount ofpolyethylene helps to enhance flow characteristics of molten resin 126such that the molten resin can be delivered from extruder 114 to nip 108in a highly controlled fashion.

Molten resin 126 is delivered to nip 108 between film 122 and loopmaterial 124. Extruder 114 is positioned about six inches to about 18inches (e.g., about 12 inches) above nip 108. Molten resin 126 isextruded through extruder die 115 at a pressure of about 2000 psi gaugeto about 3000 psi gauge (e.g., about 2400 psi gauge) and is delivered tothe nip 108 at a temperature of about 500 degrees Fahrenheit to about650 degrees Fahrenheit (e.g., about 580 degrees Fahrenheit). As aresult, a layer of resin 126 that is about 0.5 mil to about 1.5 mils(e.g., about one mil) thick is formed between film 122 and loop material124.

As shown in FIG. 1, extruder 114 has been adjusted such that moltenresin 126 is delivered approximately into the center of nip 108. As aresult, molten resin 126 contacts film 122 and loop material 124 atsubstantially the same time.

Rolls 102, 104, and 106 are configured to create a nip pressure of about10 psi gauge to about 15 psi gauge. In some embodiments, rolls 102, 104,and 106 are configured to created a nip pressure of about 12 psi gauge),which equates to a pressure of about 30 pounds per linear inch. Thepressure in pounds per linear inch can be determined as a function ofthe gauge pressure and the diameter and length of pressure roll 102. Therotation of pressure roll 102 and backing roll 104 in oppositedirections draws film 122, loop material 124, and molten resin 126through nip 108. As these materials pass through nip 108, the pressureswithin nip 108 compress resin 126 between film 122 and loop material124. The relatively low nip pressure helps to ensure that loopsextending from loop material 124, which contact the peripheral surfaceof pressure roll 102, are not damaged (e.g., do not melt) during thelamination process.

In addition, pressure roll 102 and backing roll 104 are chilled to atemperature of about 50 degrees Fahrenheit to about 80 degreesFahrenheit (e.g., about 65 degrees Fahrenheit). Cooled rolls 102 and 104facilitate cooling of molten resin 126 as it passes through nip 108. Inaddition, the reduced temperature of rolls 102 and 104 help to preventthe loops of loop material 124 from melting due to the high temperatureof molten resin 126.

It has also been found that the weight of substrate 125 of loop material124 is sufficient to prevent loops 131 of loop material 124 from meltingunder the processing conditions discussed above. At the same time, loopmaterial 124 allows the resulting composite material 121 to have adesired flexibility and, because loop material 124 is a relativelyinexpensive material, helps to keep the cost of manufacturing compositematerial 121 well below the cost of manufacturing substantiallyair-impermeable methods using certain conventional manufacturingtechniques.

FIG. 3 illustrates an enlarged schematic view of composite material 121.As shown in FIG. 3, composite material 121 includes a film layer formedof film 122, a loop material layer formed of loop material 124, and aresin layer formed of resin 126. These multiple layers are bondedtogether as a result of the lamination process described above. Inparticular, the portion of film 122 that contacts molten resin 126during the lamination process melts and becomes welded to the resinlayer. Similarly, as schematically illustrated in FIG. 3, the portionsof substrate 125 and staple fibers 127, 129 of loop material 124 thatcontact molten resin 126 during the lamination process becomeencapsulated by molten resin 126 and melt such that loop material 124becomes welded to the resin layer. Despite the high temperature ofmolten resin 126 and the fact that loop material 124 and molten resin126 are formed primarily of the same type of material (i.e.,polypropylene) and thus have similar melting temperatures, thehook-engageability of loops 131 of loop material 124 is preserved duringthe lamination process. The temperature and flow rate of molten resin126, the temperature of chilled rolls 102, 104, and the construction ofloop material 124 are selected to prevent loops 131 from melting andthus losing their hook-engageability. As a result, loops 131, whichextend from the outer surface of the loop material layer of compositematerial 121, are hook-engageable. Composite material 121 can, forexample, be engageable by the hooks of certain hook fastener products,such as HTH 819 hooks and/or HTH 851 hooks, both available from VelcroUSA (Manchester, N.H.). Thus, as a result of the manufacturing processdescribed above, composite material 121 can advantageously be used tomake products that benefit from having one or more hook-engageablesurfaces.

Referring again to FIG. 1, composite material 121 is embossed prior tobeing wound into a roll 123 around a winder 120. To emboss compositematerial 121, composite material 121 is passed through an embossingstation 150, which includes an embossing roll 152 and a rubber (e.g.,siliconized rubber) backing roll 154. A nip 156 is formed betweenembossing roll 152 and backing roll 154. Embossing roll 152 is a heated(e.g., steam-heated), steel roll that has a pattern of raisedhoneycomb-shaped areas 158 extending from its outer surface.Alternatively, embossing roll 152 can include any of various otherraised patterns, such as combinations of diamonds, squares, triangles,circles, lines, curves (e.g., sinusoidal curves), logos, etc.

Embossing roll 152 is heated to a temperature of about 300 degreesFahrenheit to about 400 degrees Fahrenheit (e.g., about 303 degreesFahrenheit), and embossing roll 152 and backing roll 154 are configuredto create a pressure of about 35 psi gauge to about 80 psi gauge (e.g.,about 65 psi gauge) within nip 156. Composite material 121 is passedthrough nip 156 at a rate of about 20 feet per minute to about 80 feetper minute (e.g., about 30 feet per minute). As composite material 121passes through nip 156, raised areas 158 of embossing roll 152 contactthe film layer of composite material 121 and compress adjacent regionsof composite material 121 between embossing roll 152 and rubber backingroll 154, forming depressions in composite material 121. It is believedthat these depressions act as natural hinge points that facilitatefolding or bending of composite material 121, as will be discussedfurther below.

In certain embodiments, the loop material layer of composite material121 provides composite material 121 with an average peel strength ofabout 30 grams per inch width to about 100 grams per inch width (e.g.,about 35 grams per inch width to about 45 grams per inch width). A testdeveloped by Velcro Group Corporation is used to determine the peelstrength of composite material 121. The test involves the use of a 1.5inch wide and 2.0 inch long sample of composite material 121 and a 1.0inch wide by 1.0 inch long sample of 851 hook tape, manufactured byVelcro USA (Manchester, N.H.). A 1.0 inch wide by 2.0 inch wide piece ofSMS nonwoven fabric is secured to the back of the hook sample usingdouble-sided tape so that a 1.0 inch wide by 1.0 inch long tab of SMSnonwoven fabric extends from the end of the hook sample. The hook tapesample is superimposed upon the composite material sample (face to face)using minimal pressure (i.e., the amount of pressure necessary to createjust enough hook and loop engagement so as to be able to continue withthe test procedure). The hook tape and composite material samples aresuperimposed in a manner such that the machine direction of the hooksample is perpendicular to the machine direction of the loop material ofthe composite sample. A roll down machine having three rollers that eachhave a weight of about 4.5 pounds, a width of about 1.75 inches, and adurometer of 80 is then used to engage the loop material of thecomposite material sample with the hooks of the hook tape sample. Therollers of the roll down machine are rolled over the superimposedsamples at a speed of 12 inches per minute. The rollers make two fullcycles over the superimposed samples, where one full cycle constitutesrolling over the entire length of the superimposed samples and then backagain. An example of a roll down machine that can be used for thisprocedure is the RD-3000 roll down machine available fromChemInstruments.

The SMS nonwoven fabric tab extending from the end of the hook sampleand the corresponding end region of the composite material sample arethen inserted into clamps of a tensile tester. The SMS nonwoven fabrictab extending from the hook tape sample is placed into a moveable, upperclamp of the tensile tester, and the end region of the compositematerial sample is placed into a stationary, lower clamp of the tensiletester. The clamps have a maximum gauge length (i.e., the openingbetween upper and lower clamps) of about 0.5 inch. With the samplessecured in the clamps, the upper clamp is moved away from the lowerclamp at a rate of 12 inches per minute. The tensile tester isconfigured to begin recording data when a force of 0.05 pounds ismeasured, and the tensile tester is configured to move the jaws apartfrom one another until the jaws are separated by at least 1.5 inches. Anexample of a suitable tensile tester is the MTS Sintech 1/S. Theabove-described test is performed at standard atmosphere (69.8-77.0degrees Fahrenheit and 45-55 percent relative humidity), and the testsamples are preconditioned in standard atmosphere for 22-26 hours priorto testing.

As the jaws are separated from one another, the tensile tester measuresthe resistance force resulting from the engagement of the hooks andloops. This average measured force over the course of separation of thesamples is then determined and divided by the width of the engagedsamples (in this case, 1.0 inch) to determine the peel strength in gramsper lineal inch. The above-described test is repeated ten times and theaverage peel strength is determined based on those ten tests.

In some embodiments, the loop material layer of composite material 121provides composite material 121 with an average shear strength of about2000 psi to about 5000 psi (e.g., about 3400 psi to about 4200 psi). Atest developed by Velcro Group Corporation is used to determine theshear strength of composite material 121. This test involves the use ofa 1.5 inch wide by 2.0 inch long sample of composite material 121 and a1.0 inch wide by 2.0 inch long sample of 851 hook tape, manufactured byVelcro USA (Manchester, N.H.). The hook tape sample is backed with a 1.0inch wide by 2.0 inch long piece of masking tape to prevent breaking ofthe hook tape sample during the test. The hook tape sample issuperimposed upon the composite material sample and the samples areengaged by a roll down machine in the manner described above. As aresult, end regions of the samples overlap by 0.5 inch. As a result, a1.5 inch length of the composite material sample extends from one end ofthe overlapped region and is not facially engaged with the hook tapesample, and a 1.5 inch length of the hook tape sample extends from theopposite end of the overlapped region and is not facially engaged withthe composite material sample. The hook tape and composite materialsamples are superimposed in a manner such that the machine direction ofthe hook sample and the machine direction of the loop material of thecomposite sample extend in the same direction. The free, non-faciallyengaged end regions of the hook tape and composite material samples arethen inserted into clamps of a tensile tester (e.g., the MTS Sintech 1/Stensile tester). The end region of the hook tape sample is placed into amoveable, upper clamp of the tensile tester, and the end region of thecomposite material sample is placed into a stationary, lower clamp ofthe tensile tester. The clamps have a maximum gauge length (i.e., theopening between upper and lower clamps) of about 2.0 inch. With the tabsof the samples secured in the clamps, the upper clamp is moved away fromthe lower clamp at a rate of 12 inches per minute. The clamps are movedapart a sufficient distance to achieve a shearing of the engaged hooktape and composite material samples. The above-described test isperformed at standard atmosphere (69.8-77.0 degrees Fahrenheit and 45-55percent relative humidity), and the test samples are preconditioned instandard atmosphere for 22-26 hours prior to testing.

As the jaws are separated from one another, the tensile tester measuresthe resistance force resulting from the engagement of the hooks andloops. The peak load (i.e., highest measured force) is then divided bythe overlap area of the samples (in this case, 0.5 inch long by 1.0 inchwide) to determine the shear strength in pounds per square inch. Theabove-described test is repeated ten times and the average shearstrength is determined based on those ten tests.

Because each of the various components or layers of composite material121 are formed primarily of the same type of material (i.e.,polypropylene), composite material 121 is recyclable. As a result,composite material 121 can be readily used in many single-use orlimited-use products, some of which are described below, in anenvironmentally conscious and cost-efficient manner.

In addition to being hook-engageable and recyclable, the combination offilm 122, loop material 124, and the cooled resin 126 therebetweencooperate to make composite material 121 substantially air-impermeable.Composite material 121 can, for example, have an air-permeability of 0cm³/s/cm² (0 ft³/min/ft²), as tested using ASTM D737-96.

After composite material 121 exits nip 108, the composite material iswound into a roll 123 around winder 120. Winder 120 can provide atension of about 50 psi gauge to composite material 121 as compositematerial 121 is wound onto winder 120. Winding composite material 121into a roll allows the composite material to be conveniently shipped orstored in mass quantities.

The exemplary method illustrated in FIG. 1 can be used to efficientlymake composite material 121 at high rates of speed. For example, themethod can be used to make composite material 121 at a rate of at leastabout 200 linear feet per minute (e.g., at least 400 linear feet perminute, at least about 600 linear feet per minute). In some cases,composite material is produced at a rate of about 200 linear feet perminute to about 800 linear feet per minute (e.g., about 400 linear feetper minute to about 600 linear feet per minute). The width of compositematerial 121 produced is typically about six feet wide. However, thecomposite material can be formed in wider or narrower swaths. As aresult of the rapid production speeds of system 100, the exemplarymethod can be used to inexpensively manufacture material that issubstantially air-impermeable, hook engageable, and recyclable.

As discussed above, composite material 121 can be used to form any ofvarious different products. An example of one such product is a medicalcompression device (e.g., a blood pressure cuff) 200, which isillustrated in FIGS. 4 and 5. Blood pressure cuff 200 includes aninflatable pouch 202 and a strap portion 204 integrally extending frominflatable pouch 202. A fitment 208 capable of coupling with a flexibletube 210 (shown in FIG. 6) that is connected to a hand-operated pump 212(also shown in FIG. 6) is in fluid communication with inflatable pouch202. As described below, inflatable pouch 202 and strap portion 204 canbe formed by folding a sheet of composite material 121 and then weldingthe overlapping halves of the folded sheet of composite material 121together. As a result of this process, welds 214 are formed around theperimeter of inflatable pouch 202 and around the perimeters of strapportion 204.

Referring to FIG. 5, loops 131 of the loop material layer of compositematerial 121 extend from the outer surfaces of inflatable pouch 202 andstrap portion 204. Loops 131, as discussed above, are hook-engageable.In addition, loops 131 provide a soft, comfortable surface forcontacting the user's skin during use. In addition, a hook fastener 216including an array of loop-engageable hooks is attached (e.g., welded)to an outer surface of strap portion 204. The hook fastener 216 isarranged so that when blood pressure cuff 200 is wrapped around apatient's arm and strap portion 204 overlaps itself, hook fastener 216can releasably engage loops 131 extending from the opposite outersurface of strap portion 204 to tightly secure blood pressure cuff 200around the patient's arm. The loop-engageable hooks of hook fastener 216can, for example, be of molded form available from Velcro, USA underdesignation HTH 819, HTH 851, or any of various other hooks that arecapable of releasably engaging loops 131 of composite material 121.Typically, the hooks are formed primarily of (e.g., entirely of) thesame polymer as the various components of composite material 121. Incertain embodiments, for example, hook fastener 216, film 122 ofcomposite material 121, and loop material 124 of composite material 121are formed substantially entirely of polypropylene, and resin 126 ofcomposite material 121 is formed primarily of polypropylene. Asdiscussed above, for example, the resin layer of composite material 121can include at least about 85 percent by weight (e.g., at least about 90percent by weight, at least about 95 percent by weight) polypropyleneand at most about 15 percent by weight (e.g., at most about 10 percentby weight, at most about 5 percent by weight) polyethylene.

FIG. 6 shows blood pressure cuff 200 wrapped around the upper portion ofa patient's arm 218. Flexible tube 210, mated with fitment 208, is usedas a conduit extending from pump 212 to fill inflatable pouch 202 withair as pump 212 is operated. This tightens blood pressure cuff 200around the patient's arm 218 until blood flow is constricted, andenables measurement of blood pressure during gradual release of air frompouch 202. Typically, automatic blood pressure detecting devices withwhich blood pressure cuff 200 can be used are adapted to sense (e.g., byaudible signal) blood passing through the patient's arm both as bloodpressure cuff 200 is inflated and as blood pressure cuff 200 isdeflated. By sensing blood passing through the patient's arm as the cuffis being inflated, the blood pressure detecting device is able todetermine the point at which blood can no longer be detected flowingthrough the patient's arm. At this point the cuff is slowly deflated.The points at which blood flow is first sensed and last sensed by theblood pressure detecting device as the cuff is being deflated can beused to indicate the systolic and diastolic blood pressure of thepatient.

It has been found that the embossed pattern of composite material 121helps to reduce the noise associated with inflating and deflating bloodpressure cuff 200. Without wishing to be bound by theory, it is believedthat the depressions formed in composite material 121 during theembossing process act as hinges and thus decrease bending resistance ofcomposite material 121. It is further believed that this decreasedbending resistance decreases the noise associated with inflating anddeflating blood pressure cuff 200, and thus improves the ability of theblood pressure detecting device to accurately identify the point atwhich blood flow through the patient's arm is no longer audible. Thiscan, for example, decrease the likelihood of the blood pressuredetecting device being prematurely unable to sense blood flow throughthe patient's arm as a result of background noise caused by theinflating cuff. As a result, the likelihood of the blood pressuredetection device deflating blood pressure cuff 200 prematurely andhaving to restart the blood pressure detection procedure can be reduced.

Due to the efficiency with which composite material 121 can bemanufactured using the various methods described herein, blood pressurecuff 200 can be manufactured relatively inexpensively. This allows bloodpressure cuff 200 to be manufactured as a limited use (e.g., single-use)device that can, for example, be used in trauma rooms or other placeswhere the cuff may become contaminated with blood or other bodily fluidsduring use. After becoming contaminated, the blood pressure cuff 200 cansimply be discarded. In addition, because the various components ofcomposite material 121 are formed primarily of the same material (e.g.,polypropylene), blood pressure cuff 200 is readily recyclable. This is abeneficial characteristic for products such as blood pressure cuff 200,which will be used only a limited number of times (e.g., ten times orfewer, or only once) before being discarded.

FIG. 7 schematically illustrates a method of manufacturing multiplemedical compression devices (e.g., blood pressure cuffs) of the typeillustrated in FIGS. 4-6. As shown in FIG. 7, this exemplary method usesa horizontal poucher system 300 to overlap (e.g., by folding) and weld asingle sheet of composite material 121 in selected bonding regions toform inflatable pouch 202 and strap portion 204 of blood pressure cuffs200. Beginning at the right side of FIG. 7, the sheet of compositematerial 121 is led from composite roll 123, which is positioned on arotatable shaft 302, into a former 304 where the composite material 121is folded about an axis A to form overlapped areas of composite material121. Once centered on former 304, composite material 121 passes throughdrive stations 306 and 308, which are located near the entry and exit,respectively, of system 300 and are coupled to act in unison. Drivestation 306 includes rolls extending the full width of the foldedcomposite material to pull the sheet-form composite through the former304. In coordination with the downstream drive station 308, drivestation 306 also tensions the material. Due to the arrangement ofcomposite material 121 on composite roll 123, after being folded, foldedregions of film 122 contact one another and loops 131 extend from theouter surfaces of the folded sheet. As a result, the outer surfaces ofthe folded composite material 121 are hook-engageable.

By indexing action, the sheet form composite material 121 passes fromformer 304 to a pair of welding stations 310 and 312 where sealing barsweld selected overlapped regions of the folded composite material 121together. The folded composite material 121 then passes from the weldstations 310 and 312 to an insertion station 314. As the foldedcomposite material 121 passes through insertion station 314, portions ofthe folded composite material 121 between welds formed by weld stations310 and 312 are engaged by a pair of oppositely acting suction cups 316.The top of the pouch between the welds is opened to enable the placementof fitment 208 in an opening between the welds.

One alternative method for opening the sides of the pouch is to useloop-engageable fasteners (e.g., hook fasteners) to engage and pull backthe loop bearing sides of the folded composite material 121. This can beused to open the sides slightly, at which time spreader blades can beinserted and spread apart to complete the action. Another method foropening is to place the fold axis A slightly off center of the overallweb width. Thus, when folded about axis A, one edge of the foldedmaterial will extend higher than the other. Given height differencebetween opposed edges, high-pressure air blown into the pouch area ormechanical means such as pinchers can open the sides.

With fitment 208 held in place at the opening, downstream drive station308, in conjunction with drive station 306, indexes the folded andwelded material from insertion station 314 to a top seal station 318.Sealing jaws of top seal station 318 with motion similar to that of theheat seal bars at weld stations 310 and 312, can be moved inward to weldthe top edge of the folded composite material 121 and can be movedoutwardly to release the top edge of the folded composite material 121.While system 300 is forming the welds at weld stations 310 and 312, andinserting fitment 208 at insertion station 314, the sealing jaws at topseal station 318 engage to seal shut the top of the folded compositematerial 121 along the portion of the folded composite material 121 thatultimately becomes strap portion 204 of blood pressure cuff 200.Simultaneously, sealing jaws at an adjacent top seal station 320 engageto weld the top edge of the folded composite material 121 to forminflatable pouch 202 of blood pressure cuff 200. This weld alsofunctions to secure fitment 208 in place. As discussed above, fitment208 can subsequently be connected to conduit 210 and pump 212 to allowinflation of pouch 202.

Downstream cutting jaws 322, 324 sever the folded composite material 121along the trailing weld adjacent inflatable pouch 202. This severs theleading blood pressure cuff preform from the remainder of the continuoussheet form composite material 121 that is in the process of being formedinto additional blood pressure cuff preforms. After severing the leadingblood pressure cuff preform from the remainder of composite material121, hook fastener 216 is welded to the blood pressure cuff preform tocomplete the formation of blood pressure cuff 200.

A repeat length L₁ for system 300 is established by the desired lengthof blood pressure cuff 200 and extends from sealing bar 310 to thedownstream weld that was previously formed by sealing bar 310.Similarly, the distance A1 between weld stations 310 and 312 areestablished by the desired length of inflatable pouch 202 of bloodpressure cuff 200.

While certain embodiments have been described, other embodiments arepossible.

In certain embodiments, for example, the embossing of composite material121 can be performed by an embossing station that is separate fromsystem 100. In such embodiments, for example, composite material 121 canbe wound onto roll and then transported to an embossing station, wherethe roll of composite material 121 is unwound and passed through a nipformed between an embossing roll and backing roll of the type describedabove.

While composite material 121 has been described as being embossed, incertain embodiments, composite material 121 is not embossed prior tobeing formed into a product, such as a compression device. In someembodiments, as an alternative to or in addition to embossing compositematerial 121, a patterned film can be introduced into nip along withmolten resin and loop material. The patterned film can facilitatefolding of the material and, in the case of blood pressure cuffs formedfrom the composite material, can help to reduce noise created by thecuff as it is inflated.

While support roll 106 of system 100 has been described as contactingpressure roll 102 to prevent or reduce bowing of pressure roll 102 as aresult of high pressures within nip 108, in certain embodiments, supportroll 106 is moved to a disengaged position such that support roll 106does not contact pressure roll 102. Such an arrangement can be used, forexample, when pressures within nip 108 are not sufficiently high tocause bowing of pressure roll 102. As an alternative to moving supportroll 106 to a disengaged position, support roll 106 can be entirelyremoved from system 100 in certain cases.

While the compression devices (e.g., blood pressure cuffs) 200 have beendescribed as being manufactured by folding composite material 121 andthen welding overlapping portions of the composite material together,other types of manufacturing techniques can be used. In certainembodiments, as schematically illustrated in FIG. 8, for example, twoseparate sheets of composite material 121 are welded together to formthe compression devices. The two sheets of composite material 121 arefed from rolls 123 in an overlapping manner. The sheets are weldedtogether using a welding process similar to the welding processdescribed above with respect to FIG. 7. However, in addition to usingtop seal stations 318 and 320 to provide welds, bottom seal stations318′ and 320′ are provided to weld the overlapped sheets of compositematerial 121 along the bottom edge of those sheets. The other steps ofthe manufacturing process can be substantially the same as those stepsdescribed above with respect to FIG. 7.

While the above-described manufacturing methods describe welding thehook fasteners to composite material 121 after the composite material ormaterials has/have been formed into the shape of the blood pressurecuffs, the hook fasteners can alternatively be welded onto compositematerial 121 prior to forming the composite material into the shape ofblood pressure cuffs. For example, before winding composite material 121onto winder 120, composite material can pass through a welding stationthat welds hook fasteners at longitudinally spaced apart regions of thecomposite material. As a result, after forming the composite materialinto blood pressure cuffs, the hook fasteners will be located only alonga desired portion of the length of the blood pressure cuffs.

Alternatively, prior to winding composite material 121 onto winder 120,the composite material can pass through a welding station thatcontinuously welds one or more hook fastener strips to the compositematerial. The hook fastener strips can, for example, be provided in aroll and can be delivered to a nip formed between a support roll and athermal sealing member. In some embodiments, the hook fastener stripscan be provided as continuous strips that extend along the entire lengthof the blood pressure cuff.

While the hook fasteners have been described as being welded tocomposite material 121, other techniques can be used. In someembodiments, for example, the hook fasteners are joined in situ tocomposite material 121. In such embodiments, composite material 121 maybe passed through a nip formed between a mold roll including hook-shapedcavities and a pressure roll along with molten resin. The molten resinis pressed into the hook-shaped cavities to form hooks. At the sametime, the molten resin bonds to composite material 121. The generalconcept of in situ lamination is explained in U.S. Pat. No. 5,260,015 byKennedy et al., and in situ lamination of strips of molded hooks, perse, is disclosed in U.S. Pat. No. 6,205,623 by Shepard et al., which arehereby incorporated by reference herein.

While the compression devices 200 have been described as blood pressurecuffs, other types of compression devices can be manufactured usingmethods similar to those described above. FIG. 9, for example,illustrates a sequential compression device 400 that can be manufacturedusing the composite material described above and using methods similarto those described above. Sequential compression device 400 is adisposable wrap that includes multiple inflatable compartments 402. Afitment 408 is connected to each of the inflatable compartments 402.Fitments 408 permit a tube from a pump (e.g., an air pump) to beconnected thereto to allow inflatable compartments 402 to be selectivelyinflated and deflated. A hook fastener strip 416 is attached to thepolymeric film of the composite material of compression device 400 alongthe lower edge of compression device 400. Loop material 131 extends fromthe outer surface of the composite material opposite hook fastener strip416, and thus is shown in dashed lines. As shown in FIG. 10, hookfastener strip 416 can engage loop material 131 to form a sleeve havingmultiple annular inflatable compartments along its length.

During use, sequential compression device 400 is secured in the form ofa sleeve around a limb (e.g., a leg) of a patient by wrapping thecomposite material around the limb of the patient and then fastening thehooks of hook fastener strip 416 to loop material 131. Each of theinflatable compartments 402 is then connected to a pump (e.g., an airpump) via separate tubes. Compartments 402 are then sequentiallyinflated and deflated. Using sequential compression device 400 in thismanner can improve blood flow and prevent clot formation. Such use canhelp to prevent the development of deep vein thrombosis (DVT) andsimilar conditions in immobile patients.

Sequential compression devices 400 can be formed using systems andmethods similar to those illustrated in FIGS. 7 and 8. However, thesystem would typically be equipped with additional welding stations thatcan be used to form the increased number of inflatable compartments 402along the length of sequential compression device 400. In addition, hookfastener strip 416 would be applied along one of the lengthwise edges ofcompression device 400.

While compression device 400 has been described as having a hookfastener strip that engages loop material to form a sleeve, in certainembodiments, opposite edge regions of the compression device arethermally welded to form a permanent sleeve. In such embodiments, priorto use, the compression device would be slid onto the limb of thepatient rather than being wrapped around the patient's limb and thenfastened.

In addition to blood pressure cuffs and sequential compression devices,various other types of compression devices can be manufactured using thecomposite material described above. One such device is an inflatabletourniquet cuff. The inflatable tourniquet cuff can be formed andoperated in substantially the same manner as the blood pressure cuffsdescribed above. Tourniquet cuffs can, however, be provided in a widerange of sizes to allow the tourniquets be used on various differentbody parts of different patients. Some inflatable tourniquet cuffs can,for example, be sized to fit around a patient's arm and other inflatabletourniquet cuffs can be sized to fit around a patient's leg. Suchtourniquet cuffs can be used to prevent blood flow to the patient's armor leg during use. For example, during a surgical procedure on apatient's arm, the arm-sized cuff can be wrapped around the patient'sarm and then inflated to stop blood flow to the patient's arm.Similarly, during a surgical procedure on a patient's leg, the arm-sizedcuff can be wrapped around the patient's leg and then inflated (e.g., byconnecting a tube from a pneumatic pump to the fitment of the tourniquetcuff and operating the pump) to stop blood flow to the patient's arm.Use of the tourniquet cuffs in this manner can permit the surgeon towork in a bloodless operative field. Smaller tourniquet cuffs can alsobe made for use on smaller limbs, such as fingers and toes, of patients.

Another type of device that can be manufactured using the compositematerials described above is an inflatable immobilizing device, such asan inflatable cast. Such casts can, for example, be sized and shaped foruse on a patient's ankle or wrist.

While film 122 has been described as a two mil thick, cast,polypropylene film. Other types of films can alternatively be used. Forexample, films having a thickness of about 1 mil to about 5 mils can beused.

While loop material 124 has been described as including a 17 grams persquare meter spunbond polypropylene substrate through which staplefibers 127 and 129 are needled, other types of nonwoven fabrics canalternatively be used to form the substrate of the loop material. Insome embodiments, for example, staple fibers 127 and 129 are needledthrough a 30 grams per square meter polypropylene SMS substrate to formthe loop material. In such embodiments, any of the various needlingmethods described or referenced above can be used to make the loopmaterial. The resulting loop material has an overall basis weight ofabout 1.7 osy to about 2.0 osy.

In some embodiments, materials other than nonwoven materials are used asthe substrate of the needled loop material. Examples of such materialsinclude films and knits.

While loop material 124 has been described as including loops formed ofstaple fibers available from Asota Mills, under product numbers L10D andCL10, it should be understood that various other types of staple fiberscan be used so long as those staple fibers are capable of being needledthrough a substrate to form loops and are formed of a material desiredfor the particular composite material being formed (e.g., formedsubstantially entirely of a certain type of polymeric material, such aspolypropylene).

As an alternative to the needled loop materials described above, incertain embodiments, other types of hook-engageable materials can beused. Examples of such hook-engageable materials include SMS fabric,spunbond fabric (e.g., spunbond polypropylene (commodity grade)), andknits. However, we have found the above-described needled loop materialsto be particularly advantageous in certain cases because they typicallyprovide longer useful life expectancies, and it is believed that theneedled loop materials are particularly effective at preventing thehook-engageable fibers (i.e., loops) from being destroyed (e.g., bymelting) during manufacturing processes that involve the application ofmolten resin to the needled loop material.

While molten resin 126 has been described as a mixture of polymers(i.e., polypropylene and polyethylene), in certain embodiments, themolten resin is formed entirely of a single polymer (e.g.,polypropylene).

While the film, hook-engageable material, and molten resin of thosecomposite materials discussed above have been described as being formedprimarily of or entirely of polypropylene, they can alternatively beformed primarily of or entirely of other materials. In certainembodiments, for example, the film, hook-engageable material, and moltenresin are formed primarily of or entirely of polyethylene. Compositematerials of this construction can, for example, be advantageous forapplications that benefit from increased flexibility or stretchabilitywhile still providing a substantially air-impermeable barrier.Alternatively, the film, hook-engageable material, and molten resin canbe formed primarily of or entirely of nylon (e.g., lightweight nylonknit).

While certain composite materials discussed above have been described asbeing substantially air-impermeable, in certain embodiments, thecomposite material is not air-permeable. In some embodiments, forexample, the composite material is liquid-impermeable but isair-permeable. One example of such a composite material is made with aperforated polymeric film. The perforations are sized such that liquidis unable to pass through the film while air and other gases are allowedto pass through the perforations. Such composite materials can beuseful, for example, for forming products that benefit fromliquid-impermeability but are not required to be inflatable.

In addition to the compression devices described above, any of variousother types of products can be manufactured using the compositematerials described herein. In some embodiments, for example, medicalcold wraps can be formed using manufacturing processes similar to thosedescribed above. In certain embodiments, for example, rather thanplacing a valve or fitment into a pouch formed by the composite materialor materials, the pouch can be filled with a cooling liquid, such as acooling chemical solution or water, and then the composite material ormaterials can be welded in a manner to seal the cooling liquid withinthe pouch. Such a product can, for example, be used as a medical coldwrap that can be secured around a body part of a user to cool the bodypart. To use this type of product, the product would be placed in afreezer until the cooling liquid is cooled to a desired temperature andthen wrapped around the user's body part and fastened to cool the bodypart. Such products are useful, for example, to reduce swelling of thebody part. Examples of similar wraps are described in US 2004/0181156,which is incorporated by reference herein. In addition to theabove-described compression devices and medical wraps, any of thevarious other types of products described in US 2004/0181156 can bemanufactured using the composite materials described herein.

In some embodiments, the composite material is used in the constructionof urinary drain bags. As shown in FIG. 11, for example, a urinary drainbag 500 includes a first wall 502 formed from the liquid-impermeable andhook-engageable composite material of the type described above. A secondwall 504 of drain bag 500 is formed of a liquid-impermeable polymericfilm. The loop layer of the composite material is exposed along an outersurface of the rear wall of drain bag 500. In this manner, drain bag 500can be releasably fixed to any surface having engageable hooks extendingtherefrom. In certain cases, for example, hook tape can be applied to ahospital bed and drain bag 500 can be conveniently secured to thehospital bed by engaging the loops of the composite material to thehooks of the hook tape. Such an arrangement can make it easier for drainbags to be replaced by medical personnel. Any of various other types ofmedical bags that would benefit from being releasably secured to asurface can similarly be formed from the hook-engageable compositematerials described herein.

Referring again to FIG. 1, while molten resin 126 has been described asbeing introduced directly into nip 108 such that molten resin 126contacts film 122 and loop material 124 at substantially the same time,in certain embodiments, molten resin 126 is applied first to film 122,and film 122 then carries molten resin 126 into nip 108. This techniquecan provide molten resin 126 with additional time to cool prior tocontacting loop material 124, which can help to prevent loops 131extending from the outer surface of loop material 124 from melting andbecoming bonded together. As a result, this technique can help to ensurethat loops 131 extending from loop material 124 remain capable ofengaging hooks of hook fastener elements after loop material 124 isbonded to film 122 to form the composite material.

While the composite materials of embodiments above have been describedas including a hook-engageable surface, in certain embodiments,composites having only surfaces that are not hook-engageable are formed.Such composites can be formed using manufacturing processes similar tothose described above. In certain embodiments, for example, a needledloop material having a 17 grams per square meter spunbond polypropylenesubstrate is fed into nip 108 formed between pressure roll 102 andbacking roll 104. Molten resin is applied to the loop material to form aresin layer that is about 2 mils thick. The loop material then carriesthe molten resin into nip 108. Due to the relatively thin substrate ofthe loop material, the increased amount of molten resin, and theextended duration of contact between the molten resin and the loopmaterial, the molten resin drowns the loops extending from the loopmaterial. This causes the loops extending from the outer surface of theloop material (i.e., the surface in contact with the PTFE coated roll)to melt and become bonded to one another. As a result, the loop materiallayer of the resulting composite material does not readily engage hooksof hook fastener elements. Such a construction can, for example, beadvantageous for products in which a soft non-hook-engageable outersurface is desired.

Other embodiments are within the scope of the following claims.

1. A method of forming a composite material, the method comprising:introducing a sheet-form film and a hook-engageable material into a nipformed between a first roll and a second roll; introducing molten resininto the nip between the film and the hook-engageable material; andallowing the molten resin to cool so that the film becomes attached tothe hook-engageable material by the cooled resin, wherein each of thefilm, the hook-engageable material, and the molten resin includes atleast about 85 percent by weight of a first polymer.
 2. The method ofclaim 1, wherein the composite material is substantiallyair-impermeable.
 3. (canceled)
 4. The method of claim 1, wherein fibersextending from a surface of the hook-engageable material are capable ofengaging hooks of hook fasteners after the film is attached to thehook-engageable material by the cooled resin.
 5. The method of claim 1,wherein the first polymer is polypropylene.
 6. The method of claim 5,wherein the film and the hook-engageable material consist essentially ofpolypropylene.
 7. The method of claim 6, wherein the molten resin is atleast about 90 percent by weight polypropylene.
 8. The method of claim7, wherein the molten resin further comprises polyethylene.
 9. Themethod of claim 1, wherein the hook-engageable material comprises a 17grams per square meter spunbond polypropylene substrate through which aplurality of loop shaped staple fibers extend.
 10. The method of claim1, wherein the hook-engageable material comprises a 30 grams per squaremeter SMS polypropylene substrate through which a plurality of loopshaped staple fibers extend.
 11. The method of claim 1, wherein themolten resin introduced into the nip has a thickness of about one mil,the film has a thickness of about three mils, and the hook-engageablematerial has a weight of about 1.3 to about 2.0 osy.
 12. (canceled) 13.The method of claim 1, wherein the molten resin is at a temperature ofat least about 500 degrees Fahrenheit when introduced into the nip.14-15. (canceled)
 16. The method of claim 1, wherein the film is a castfilm.
 17. The method of claim 1, wherein the molten resin is introducedinto the nip in a manner such that the molten resin contacts the filmand the hook-engageable material at substantially the same time.
 18. Themethod of claim 1, wherein the molten resin is introduced into the nipby applying the molten resin to the hook-engageable material androtating the first and second rolls to carry the film, thehook-engageable material, and the molten resin into the nip.
 19. Themethod of claim 1, wherein the molten resin is introduced into the nipby applying the molten resin to the film and rotating the first andsecond rolls to carry the film, the hook-engageable material, and themolten resin into the nip.
 20. The method of claim 1, wherein at leastone of the first and second rolls is chilled to facilitate cooling ofthe molten resin.
 21. (canceled)
 22. The method of claim 1, furthercomprising embossing the composite material.
 23. The method of claim 22,wherein embossing the composite material comprises passing the compositematerial between an embossing roll and a backing roll, the embossingroll have a plurality of raised features that compress the compositematerial between the embossing roll and the backing roll.
 24. The methodof claim 23, wherein the embossing roll is a heated roll.
 25. A methodof forming a composite material, the method comprising: introducing asheet-form film and a hook-engageable material into a nip formed betweena first roll and a second roll; introducing molten resin into the nipbetween the film and the hook-engageable material; and allowing themolten resin to cool so that the film becomes attached to thehook-engageable material by the cooled resin, wherein each of the film,the hook-engageable material, and the molten resin includes at leastabout 90 percent by weight of a first polymer, the composite material issubstantially air-impermeable, and fibers extending from a surface ofthe hook-engageable material are capable of engaging hooks of hookfasteners after the film is attached to the hook-engageable material bythe cooled resin.